Echocardiographic Flow Pattern of Patent Ductus Arteriosus in Preterm Infants with Respiratory Distress: Compared with Other Echocardiographic Parameters

Objective: The different patterns of ductal shunt flow by Doppler echocardiography are useful for the diagnosis and prediction of risk of hemodynamically significant patent ductus arteriosus (PDA), especially growing or pulsatile patterns. We examined whether the ductal flow patterns might represent a reliable guide for PDA management in preterm infants with respiratory distress, using a comparison of traditional echocardiographic parameters. Methods: Thirty-one preterm infants with gestational age of 25-34 weeks who required respiratory supports were studied. Serial echocardiographic evaluations were performed within the first week after birth. Four ductal flow patterns were identified such as pulmonary hypertension pattern, growing pattern, pulsatile pattern and closing pattern and compared with other echocardiographic indices. Results: One hundred five echocardiographic evaluations were done. The ductal diameter varied widely within each pattern but was significantly associated with ductal flow pattern: median diameter was greatest in the pulmonary hypertension pattern, progressively narrowed across the growing and pulsatile patterns, and was smallest in the closing pattern. The ratio of the ductal diameter to weight, the ratio of the left atrial to aortic root diameter and the diastolic flow velocity in left pulmonary artery of the growing and pulsatile patterns were significantly higher than those of the pulmonary hypertension and closing patterns. Conclusion: Echocardiographic Doppler assessment of shunt flow pattern is useful for diagnosis of hemodynamically significant PDA in premature infants, especially in the growing or pulsatile pattern. The addition of ductal flow pattern assessment to traditional echocardiographic measures may further enhance the clinical diagnostic capacity of echocardiography for PDA.